Glucocerebrosidase catalyzes the conversion of glucosylcermides to ceramides which are critical components of the epidermal permeability barrier. Inhibition or deficiency of epidermal glucosylcerebrosidase results in altered barrier function. For example, Gaucher's disease is a genetic disorder caused by a deficiency of this enzyme which results in the accumulation of glucosylceramides in cells throughout the body. In order to gain further understanding of the biological role of this enzyme and also to control the enzyme in biological systems, it is necessary to study the structures of its natural substrates or analogs. Physical analytical methods such as mass spectrometry will be very necessary to assist in obtaining the goal of this study.